Anelastic relaxation mechanisms characterization by Mossbauer spectroscopy

Anelastic behavior of crystalline solids is generated by several microstructural processes. Its experimental study yields valuable information about materials, namely: modulus, dissipation mechanisms and activation enthalpies. However, conventional techniques to evaluate it are complicated, expensive, time consuming and not easily replicated. As a new approach, in this work a Mossbauer spectrum of an iron specimen is obtained with the specimen at repose being its parameters the "base parameters." After that, the same specimen is subjected to an alternated stress-relaxation cycle at frequency omega(l) and a new Mossbauer spectrum is obtained tinder this excited conditions doing the same at several increasing frequencies omega(n) in order to scan a wide frequencies spectrum. The differences between the Mossbauer parameters obtained at each excitation frequency and the base parameters are plotted against frequency, yielding an "anelastic spectrum" that reveals the different dissipation mechanisms involved, its characteristic frequency and activation energy. Results are in good agreement with the obtained with other techniques.